Patient-Surgeon Sex Mismatch Doesn’t Drive Disparities in Cardiac Surgery

The search for the reason why women have worse surgical outcomes than men continues.

Sex discordance isn’t an explanation for gender disparities in outcomes after cardiac surgery, new data suggest. For men, whether their surgeon was male had no impact on morbidity and mortality at 30 days or 5 years. Similarly, women had the same outcomes regardless of whether they were treated by a female or male surgeon.

The study, led by Lamia Harik, MD, and Alexander C. Gregg, MD (both from Weill Cornell Medicine, New York, NY), was published recently in the Journal of the American Heart Association.

Speaking with TCTMD, Harik said that the concept of sex discordance is fairly novel and that it’s the first time such a lens has been applied to cardiac surgery. Literature on general surgery has suggested the factor might explain sex disparities, though this is not what they found here.

Mario Gaudino, MD, PhD (Weill Cornell Medicine), noted that it’s well known that women generally fare worse than men after cardiac surgery.

“This is something that is becoming more and more evident. I think we as a community are guilty of the fact that we have ignored this issue for a long time,” he told TCTMD. Many had hoped the gap would narrow as cardiac surgery as a whole improved, but “this is not the case. There is still a very large gap in outcome between sexes, with women having worse outcomes. So we need to investigate the reason for that.”

Gaudino and Harik suggest that cardiac surgery’s team-based approach may be why it wasn’t swayed by discordance.

“The cardiac anesthesiologist, cardiologist, interventional cardiologist, and perfusionists all play a key role in getting patients to, and through, a cardiac surgery. The surgeon is only one operator who is part of a larger team; thus, the effect of the individual surgeon on outcomes may be somewhat mitigated,” the investigators write.

On top of this, “cardiac surgery is a more standardized field than general surgery,” they note, adding that “the relatively longer training pathway of cardiac surgery may minimize technical skill disparities among surgeons, such that there is less intraoperator variability in cardiac surgery by the time attendinghood is reached.”

The idea in their research, said Harik, was to ask: “What’s modifiable? What can we actually fix rather than throwing our hands up and just sort of accepting this disparity as the status quo?” In addition to exploring concordance, Harik and colleagues previously looked at intraoperative anemia in CABG and identified it as a key mediator.

Discordance Not a Driver

The researchers analyzed data from 223,065 Medicare beneficiaries (68.2% male) who underwent coronary artery bypass grafting, surgical aortic valve replacement, and/or proximal aortic surgery from 2010 to 2021. Stratified by sex, 59.9% of the cases involved a patient and surgeon who were both male, 28.0% a female patient with a male surgeon, 8.3% a male patient with a female surgeon, and 3.8% a female patient and surgeon.

At 30 days, the mortality rate was 4.1%, while the rate of mortality plus morbidity (MI, stroke, and all-cause readmission) was 30.1%. There was no difference in the composite between men who were treated by a male versus female surgeon (27.6% vs 27.4%) or between women who were treated by a male versus female surgeon (35.5% vs 35.1%). Although there was an imbalance between the concordant and discordant groups (28.0% vs 33.6%; P < 0.001), on multivariable regression analysis the patient/surgeon mismatch was not independently associated with outcomes (OR 1.00; 95% CI 0.96-1.04). There also was no interaction between patient sex and sex discordance for outcomes (P = 0.75).

At 5 years, the morbidity and mortality rate was higher for male patients treated by a man (67.2%) than those treated by a woman (65.3%; P < 0.001). Among female patients, it was higher for those treated by a man compared with by a woman (75.7% vs 74.0%; P = 0.0006). Again, though, discordance was not independently associated with outcome (HR 1.00; 95% CI 0.98-1.02) and there was no interaction between patient sex and discordance (P= 0.89).

I think of [our study] as a starting point and not an ending point. Lamia Harik

Harik said a limitation of their study is that some Medicare beneficiaries did not have their surgeon’s sex recorded in the database. Additionally, the number of women with female surgeons was quite small. “I wouldn’t say that our retrospective study is the final word on the topic. I think of it as a starting point and not an ending point,” she stressed. Additionally, it speaks to “the need to have more female providers in cardiac surgery.”

Gaudino, for his part, noted that while their analysis didn’t confirm their initial hypothesis that sex concordance affected outcomes in this setting, it wasn’t done in vain. “ The process of eliminating hypotheses that are not true is actually very important,” he said.

Going forward, it will be important for cardiac surgery databases to collect more information on the surgeons themselves so that it’s possible to dig into any patterns that emerge, Harik and Gaudino both stressed.

The current study, Gaudino said, “represents an interesting change in the focus of outcomes research from the patient to the provider.” An example of this is the potential relevance of group dynamics, such as how different surgeons and anesthesiologists interact.

Notably, the ROMA-Women trial, the first in cardiac surgery to be devoted entirely to women, is collecting details on providers, Harik said. “ We’re collecting the kind of data that we don’t see available in current databases for our prospective randomized study.”

Gaudino urged that a key way to improve female patients’ outcomes in cardiac surgery is to have more female clinicians and investigators involved in research. “Unfortunately, there’s no doubt that one of the reasons why we have such limited information on cardiac surgery in women is because so far most cardiac surgeons have been men and research . . . has been mostly done by men,” he commented, predicting that the younger generation of cardiac surgeons, increasingly more of them female, will be better equipped to pinpoint what’s driving sex disparities.